WEBVTT 00:00.000 --> 00:03.384 Blender 4.2 is released, and there are a few things that are 00:03.385 --> 00:07.240 new for the creation of interactive tools using Geometry Nodes. 00:08.340 --> 00:12.234 You now have the power to exactly control where the 00:12.235 --> 00:16.000 tool takes effect in the 3D viewport by clicking on it. 00:16.620 --> 00:21.100 If you go to the Release Nodes page on blender.org and scroll down to the 00:21.101 --> 00:24.920 Geometry Nodes section, you can see a little demo file where I'm presenting how 00:24.921 --> 00:34.180 you can create this kind of In this video, I'm going to show you how to use the new 00:34.181 --> 00:37.360 Nodes in Blender 4.2 to create this modifier. 00:38.600 --> 00:42.200 I also recommend you to check out the other video that I made about the new 00:42.201 --> 00:45.560 Matrix socket, because that's something that we're going to be using in this video. 00:46.200 --> 00:50.100 I also made a video on the Blender YouTube channel about Node Tools that you should 00:50.101 --> 00:52.362 check out before this to get started on the 00:52.363 --> 00:54.600 basics of how to create Node Tools in Blender. 00:55.220 --> 00:56.200 So let's get started. 00:56.201 --> 00:59.732 There are a few new features for Node Tools in Blender 00:59.733 --> 01:03.300 4.2 to make it possible to interact with the 3D viewport. 01:03.900 --> 01:09.420 One aspect of this is a feature to wait for a mouse click when the tool is called. 01:09.720 --> 01:14.700 This can be combined with the information of the mouse position and the viewport 01:14.701 --> 01:18.840 transform to click exactly where you want the operation to happen. 01:19.420 --> 01:22.820 And in this video, I will show you exactly how to set this up. 01:22.821 --> 01:26.386 We will start this setup already with two Node Groups in place 01:26.387 --> 01:29.720 that you can get from the download from the example file. 01:30.200 --> 01:34.080 One is the Impact Fracture Node, which will do the actual geometry 01:34.081 --> 01:39.180 operation that we want to do by cutting into the mesh repeatedly around a center 01:39.181 --> 01:43.920 point and then the other one we will use on top of that to create some variation 01:43.921 --> 01:47.960 and explode the individual pieces that we've cut to make it more visible. 01:48.600 --> 01:52.500 We are not going to create these from scratch, but just use them from the demo 01:52.501 --> 01:54.781 file to save some time and focus on the things that 01:54.782 --> 01:58.280 really matter for the new features in Blender 4.2. 01:58.720 --> 02:00.320 So let's take a look at these new nodes. 02:00.600 --> 02:05.820 Let's add the Mouse Position node and you can see that there is the mouse X and Y 02:05.821 --> 02:10.460 position which is in pixels and the region, width and height. 02:10.860 --> 02:13.671 Both of those are regarding the region of the 02:13.672 --> 02:16.360 viewport that you are executing the tool from. 02:16.361 --> 02:22.140 If I just connect one of these to the group output and then execute the tool in 02:22.141 --> 02:26.500 edit mode, you can see the individual values as I hover over the outputs. 02:28.520 --> 02:31.614 You can use this for example to calculate the 02:31.615 --> 02:34.200 relative position of the mouse in the region. 02:34.600 --> 02:36.560 That is something that we are going to need later. 02:37.020 --> 02:41.926 So let's turn the mouse position into a vector with a Combine 02:41.927 --> 02:45.080 X, Y, Z node and do the same thing with the region size. 02:47.420 --> 02:52.240 Then we need to divide one by the other and map it to a different range. 02:53.560 --> 02:57.389 So dividing by the region size will make sure that 02:57.390 --> 03:01.840 instead of pixels, now these values go from 0 to 1. 03:02.460 --> 03:06.240 We can check that by also connecting this to the output to make sure that this is 03:06.241 --> 03:09.099 being evaluated and then when we run the tool, 03:09.100 --> 03:12.561 you can see the relative position of the mouse. 03:12.700 --> 03:15.415 Now to get a little bit more control, let's go to the 03:15.416 --> 03:18.280 options menu here and turn on the wait for click feature. 03:19.180 --> 03:23.800 This will make sure that the evaluation of the node tree only actually happens 03:23.801 --> 03:26.860 whenever we click after executing the tool. 03:27.600 --> 03:32.640 So if I click on the name of the tool here, we get a different icon for the 03:32.641 --> 03:37.540 cursor and the actual tool is only being executed whenever I click again. 03:38.000 --> 03:42.920 So now you can see the values from wherever we clicked after executing the tool. 03:42.921 --> 03:45.792 To make this relative mouse position a little bit 03:45.793 --> 03:48.660 more useful, I want to map it to a different range. 03:49.220 --> 03:53.419 So let's use the map range node and then instead of going 03:53.420 --> 03:57.400 from 0 to 1, I want to map it to going from negative 1 to 1. 03:57.640 --> 04:00.699 But let's make sure to zero out all those Z 04:00.700 --> 04:04.901 components since we're dealing with a 2D vector. 04:05.040 --> 04:07.207 And now let's execute the tool again clicking 04:07.208 --> 04:09.961 somewhere in the middle of the viewport. 04:10.340 --> 04:14.720 And then this gives us a value around 0, which is exactly what we want. 04:15.600 --> 04:18.240 So this is the relative mouse position that we'll need. 04:18.680 --> 04:22.500 Next let's find out some information about the 3D viewport that we're looking at. 04:22.780 --> 04:24.920 So let's add the viewport transform node. 04:26.300 --> 04:29.480 And this one presents us with two matrices and a boolean input. 04:29.800 --> 04:33.780 The matrices help you with the space transformation for the viewport. 04:33.920 --> 04:36.616 One is for the camera projection and the other 04:36.617 --> 04:39.821 one for the transformation of the viewport. 04:39.920 --> 04:43.600 And this boolean just tells you whether the projection of the camera is orthographic. 04:43.960 --> 04:49.140 For now let's just simply use the view transformation matrix to find out from 04:49.141 --> 04:51.580 what point we are actually looking as the viewer. 04:52.060 --> 04:55.142 Here I'm not going to go into detail about math or 04:55.143 --> 04:57.821 how different projections and transformations work. 04:57.920 --> 05:00.960 I'm just going to show you how you can get this specific effect to work. 05:01.200 --> 05:03.541 There are plenty of learning resources online to figure 05:03.542 --> 05:06.120 out more about this kind of concept if you want to. 05:06.121 --> 05:10.500 The view transform matrix gives us the transformation into camera space. 05:10.780 --> 05:17.161 So to get the location of the camera in our object space we need to invert the matrix. 05:17.480 --> 05:21.380 And from that we can separate the individual transform components. 05:23.160 --> 05:27.880 Now this translation here gives us the exact position of the viewpoint. 05:28.340 --> 05:34.440 So wherever we are looking from at this cube will be the translation here. 05:34.441 --> 05:38.360 Let me prove this to you by adding a mesh line node. 05:38.600 --> 05:42.440 Setting this to endpoints and connecting the translation to both. 05:43.080 --> 05:46.400 And let's just replace the output of the tool with this geometry. 05:46.780 --> 05:49.576 So now wherever this location that we just calculated 05:49.577 --> 05:52.241 is, the tool is going to create a bunch of points. 05:54.340 --> 05:55.700 So let's just run the tool. 05:56.080 --> 05:57.080 Click. 05:57.880 --> 06:00.410 And now if I zoom out you can see that the 06:00.411 --> 06:04.221 points are exactly where I was looking from. 06:04.500 --> 06:05.780 Try that again. 06:08.300 --> 06:09.300 And there you go. 06:09.800 --> 06:13.880 Let's bring back our cube and then add some more nodes. 06:15.280 --> 06:17.460 This here is going to be our viewpoint. 06:18.660 --> 06:24.120 The goal with this setup is to create a raycast from the viewpoint, so from where 06:24.121 --> 06:27.300 we are looking, to the direction of the cursor. 06:27.920 --> 06:31.817 So as we are looking at the cube we want to cast a ray 06:31.818 --> 06:35.640 from the source of our view to where we are pointing. 06:36.400 --> 06:40.388 The viewpoint as the source we already have, as 06:40.389 --> 06:44.000 well as the relative mouse position in the window. 06:44.300 --> 06:48.340 All that is left to do is figure out the direction that we are pointing in. 06:49.460 --> 06:52.307 For that we can use the relative mouse position 06:52.308 --> 06:55.320 in combination with a little bit of matrix math. 06:56.360 --> 06:59.800 Again here I will just apply the math without giving too much background. 07:00.020 --> 07:03.565 But essentially we need to do both the transformation 07:03.566 --> 07:07.880 and the projection of the coordinates into view space. 07:08.340 --> 07:14.880 So we combine these two matrices using a multiply matrices node and then inverting 07:14.881 --> 07:17.420 the result to get the opposite transformation. 07:18.060 --> 07:24.180 And this we can use to project the relative mouse position from view space 07:24.181 --> 07:28.360 into the object space using the project point node. 07:29.140 --> 07:31.847 And plugging in the previous transformation, this 07:31.848 --> 07:35.420 gives us the point that we are clicking on in 3D. 07:35.840 --> 07:40.349 So let me use the previous mesh line setup to prove what 07:40.350 --> 07:43.160 that looks like by connecting this to the end location. 07:43.960 --> 07:49.155 If I run the tool you can see how we get a short line 07:49.156 --> 07:52.540 that is exactly going in the direction of our click. 07:54.700 --> 07:56.622 And things are going to be a little bit more 07:56.623 --> 07:59.161 clear once we actually do the raycasting. 07:59.380 --> 08:00.560 So let's do that next. 08:02.000 --> 08:03.540 Let's add a raycast node. 08:04.680 --> 08:08.480 And as the target geometry we are going to use our group input. 08:09.460 --> 08:13.800 And then for the source position of the raycast we can simply use the view point. 08:15.420 --> 08:17.939 And for the direction we need to calculate the 08:17.940 --> 08:20.500 difference between the two points that we just got. 08:20.501 --> 08:23.295 So use a subtract node and then subtract the 08:23.296 --> 08:26.641 view point from the point that we click on. 08:26.920 --> 08:28.320 And that will be the ray direction. 08:29.960 --> 08:34.340 To visualize the result of this raycast let's still use our mesh line. 08:34.700 --> 08:40.861 We simply need to swap out the end location with the hit location of that raycast. 08:40.960 --> 08:46.300 Let's join the result of the mesh line with our cube and try this out. 08:47.440 --> 08:48.380 And there you go. 08:48.381 --> 08:55.320 A nice simple setup to get exactly the line of our raycast from the point where 08:55.321 --> 08:59.300 you are viewing from to the point that we are clicking on in the 3D viewport. 08:59.620 --> 09:01.260 Raycast it onto our geometry. 09:01.840 --> 09:04.281 So this is the basic setup for the raycasting 09:04.282 --> 09:06.921 that you can use in all sorts of contexts now. 09:07.080 --> 09:11.580 To use the information of both the orientation of the viewport and your 09:11.581 --> 09:14.600 position of the mouse to make tools more interactive. 09:15.240 --> 09:17.654 So now we have all the information that we need 09:17.655 --> 09:20.180 and let's connect the operation of the fracturing. 09:20.181 --> 09:23.260 Let's get rid of this mesh line setup because we don't need this anymore. 09:23.440 --> 09:26.380 And instead put in the impact fracture node. 09:27.380 --> 09:31.120 For the center point we can simply plug in our hit position. 09:32.040 --> 09:35.780 And for the direction we can take the direction of the raycast. 09:37.060 --> 09:41.980 Let's bump up the iterations to something like 20 and take a look if that works. 09:42.680 --> 09:44.900 Yeah, that's already working great. 09:45.160 --> 09:48.535 But one thing right now is that it's not working super well 09:48.536 --> 09:51.440 whenever we have multiple mesh islands already fractured. 09:51.860 --> 09:55.842 What I want to do is to only apply the fracture operation 09:55.843 --> 09:59.020 on the mesh island or cell that I am clicking on. 09:59.420 --> 10:01.700 So let's include that mechanism in the setup. 10:02.180 --> 10:05.240 For that we can use the existing raycast operation. 10:06.300 --> 10:10.880 Let's change the data type to integer and add a mesh island node. 10:12.080 --> 10:14.807 Here we can sample the island index of the 10:14.808 --> 10:17.560 geometry that we are hitting with the raycast. 10:17.760 --> 10:21.420 So that way we know which mesh island we are actually clicking on. 10:22.740 --> 10:26.400 This information we can use to separate the geometry. 10:27.280 --> 10:33.680 We can just compare the island index with the result of the raycast. 10:35.580 --> 10:40.020 That way we separate the geometry of the mesh island that we click on from the rest. 10:40.021 --> 10:44.793 So let's only create the fracture on the selection and 10:44.794 --> 10:48.620 then afterwards join it back with the remaining geometry. 10:49.780 --> 10:51.280 Let's take a look at how that works. 10:52.060 --> 10:53.060 And there you go. 10:54.380 --> 10:57.040 Now there are just a few more things left to do. 10:57.460 --> 11:03.321 Let's reset our cube and then I want to control the selection of this tool as well. 11:03.820 --> 11:07.711 Let's set the selection after we join the geometry 11:07.712 --> 11:10.440 back to just the selection of the fracture. 11:11.060 --> 11:14.820 That way we only select the freshly fractured parts of the mesh. 11:17.000 --> 11:21.640 And on top of this as a last piece I just want to add the randomize operation. 11:23.920 --> 11:27.780 That will create a more interesting result by breaking up the shape. 11:28.360 --> 11:32.200 Let's make this tool a little bit more useful by exposing some of the parameters. 11:32.740 --> 11:38.460 Simply use the existing inputs from these node groups and drag and drop some inputs. 11:40.360 --> 11:44.280 The seed we can reuse also for the random islands operation. 11:45.300 --> 11:47.240 And then let's also expose these two. 11:48.800 --> 11:51.640 So now we have some additional control in the tool settings. 11:52.780 --> 11:56.060 The last thing that I want to do is add some additional randomization. 11:56.500 --> 11:59.573 Right now whenever we execute the tool it has the exact 11:59.574 --> 12:02.840 same seed so we get the same pattern for the fracturing. 12:03.080 --> 12:04.940 Unless we change the seed manually. 12:05.220 --> 12:08.520 But there is a small trick that I want to apply using one of the new nodes. 12:09.500 --> 12:14.260 Since we are probably not going to click in the exact same spot again we can just 12:14.261 --> 12:17.920 use the mouse position to give us a random input. 12:18.640 --> 12:22.000 So on top of the seed we can add a random value. 12:23.760 --> 12:24.760 A random integer. 12:25.560 --> 12:29.500 Let's say between negative ten thousand to positive ten thousand. 12:29.820 --> 12:35.520 That we create from the mouse X and mouse Y as the ID and the seed. 12:36.320 --> 12:39.280 And this is what we use for the seed instead. 12:40.040 --> 12:45.580 So we both have a manual seed that we can pick in combination with a random seed. 12:46.020 --> 12:47.420 Depending on our mouse position. 12:51.000 --> 12:55.180 We can also swap that out with the seed we use for the randomization of the islands. 12:56.920 --> 12:58.240 Let's get ourselves a new cube. 12:59.960 --> 13:00.960 And there you go. 13:01.420 --> 13:03.100 That's the fracturing tool done. 13:04.720 --> 13:05.400 And that's it. 13:05.560 --> 13:08.279 So that should get you up to speed to create more 13:08.280 --> 13:11.660 interactive custom tools for Blender 4.2 and onwards. 13:12.300 --> 13:13.300 Bye!